Lead alloy



Patented Sept. 3, 1935 UNITED STATES PATENT OFFICE LEAD ALLOY Robert H. Canfield and Herman F. Kaiser, Washington, D. C.

No Drawing. Application June 7, 1934, Serial No. 729,468

1 Claim.

This invention relates to alloys of lead and certain alkaline earths, which alloys are particularly adapted for use as anodes in storage batteries.

It is the object of this invention to provide alloys of increased hardness and durability and having greater resistance to attack by atomic oxygen than do the alloys heretofore known and used.

In our copending application Serial No. 697,144, filed November 8, 1933, we have disclosed and claimed certain lead alloys having improved characteristics of hardness and strength due to the inclusion in the alloy of small percentages of barium, calcium and strontium. We have found that the addition of from 0.2% to 2.0% of tin to such alloys greatly augments the above mentioned qualities. For instance, an alloy of lead comprising 0.4% strontium, 1.0% tin, and the rest lead has a Brinell hardness of over 15 as compared with a hardness of 9 for an alloy containing 0.4% strontium and the remainder lead. Our experiments have shown that the presence of tin in small proportions up to 2.0% of the weight of the alloy has a very favorable effect in increasing the resistance of the alloy to attack by atomic or nascent oxygen when the alloy is used as the anode in an electrolytic cell containing dilute sulphuric acid. In this case the penetration of oxide into the interior of the alloy and the resulting intercrystalline embrittlement is notably retarded by the specified percentages of tin.

While in general we obtain good results with alloys containing from 0.2% to 1.5% of one of following compositions: 5

Strontium from 0.2% to 0.6%, tin from 0.2% to 2.0%, and the remainder lead;

Calcium from 0.2% to 1.5%, tin 0.2% to 2.0%, and the balance lead;

Barium from 0.5% to 1.5%, tin 0.2% to 2.0%, and the rest lead.

However, any two or all three of the metals barium, calcium and strontium may be used in the same alloy, providing the total percentage thereof lies between 0.2% and 1.5%, the quantity of tin being as above mentioned. It is to be understood that all percentages are to be taken by weight.

While we have mentioned a specific use for which our alloys are especially well suited, it is 20 to be understood that their field of application is not limited thereto but that they will be found to have characterisics desirable for oher purposes than the one specified by way of illustration.

The invention herein described may be manu- 25 factured and used by or for the Government of the United States of America for governmental purposes, without the payment of any royalties thereon.

We claim:

An alloy consisting of strontium from 0.2% to 0.6% and tin from 0.2% to 2.0%, by weight, and the balance lead.

ROBERT H. CANFIELD. HERMAN F. KAISER. 

